Space heater particularly for vehicles

ABSTRACT

A space heater particularly for vehicles which have a water cooled internal combustion engine comprises a housing having a space heating air inlet and a discharge spaced from the inlet with a gas/air-heat exchanger and a liquid/air-heat exchanger located in said housing between the inlet and outlet. Space heating air is circulated through the housing by a fan to direct it preferably through the gas/air-heat exchanger and then through the liquid/air-heat exchanger before it is used for space heating. The device includes a separate burner which supplies combustion gases to the gas air heater particularly when the engine is not hot enough to supply high temperature liquid to the liquid air heater. The burner includes a combustion chamber for generating combustion gases and means for admitting fresh air to the gases in order to cool them before they are directed to the gas/air-heat exchanger. In order to make sure that the gas/airheat exchanger does not cause any contamination of the space heating air, a suction fan is connected to the outlet of the gas/air-heat exchanger to withdraw the combustion gases after they are circulated therethrough.

Koiink SPACE HEATER PARTICULARLY FOR v VEHICLES [75] Inventor: Siegfried Kofink, Zell/Necka Germany [73] Assignee: J. Eberspacher, Nackar, Germany [22] Filed: May 2, 19 73 [21] Appl. No.: 356,382

[30] Foreign Application Priority Data I May 20, 1972 Germany 2224711 [52] 11.8. C1. 237/12.3 C, 126/110 B, 431/351 [51] Int. Cl B60h l/08 [58] Field of Search 237/123 C; 126/110 R,

[56] References Cited I UNITED STATES PATENTS 2,053,037 9/1936 Lintern 126/110C 2,235,967 3/1941 Sunday 237/123 C 2,374,606 4/1945 McCollum 237/123 C 2,440,447 4/1948 McCollum 237/123 C 2,654,219 10/1953 Zaba 431/352 2,806,516 /1957 Brola 431/352 3,046,973 7/1962 Kofink 126/10 R 3,168,244 2/1965 Cospodar 237/123 C 3,304,004 2/1967 Hraboweckyj 237/123 C 3,587,490 6/1971 Martin 431/157 1 Jan. 21, 1975 Primary Ex aminerMeyer Perlin Assistant Examiner-W. E. Tapolcai, Jr. Attorney, Agent, or FirmMcGlew and Tuttle [57] ABSTRACT Aspace heater particularly 'for vehicles which have a water cooled internal combustion enginecomprises a housing having a space heating air inlet and a discharge spaced from the inlet with a gas/air-heat ex changer and a liquid/air-heat exchanger located in said housing between the inlet and outlet. Space heating air is circulated through the housing by a fan to direct it preferably through the 'gas/air-h'eat exchanger and then through the liquid/air-heat exchanger before it is used for space heating. The device includes a separate burner which supplies combustion gases to the gas air heater particularly when the engine is not hot enough to supply high temperature liquid to the liquid air heater. The burner includes a combustion chamber for generating combustion gases and means for admitting fresh air to the gases in order to cool them before they are directed to the gas/air-heat exchanger. In order to make sure that the gas/air-heat exchanger does not cause any contamination of the space heating air, a suction fan is connected to the outlet of the gas- /air-heat exchanger to withdraw the combustion gases after they are circulated therethrough.

3 Claims, 2 Drawing Figures FIG.

SPACE HEATER PARTICULARLY FOR VEHICLES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to the construction of space heaters and, in particular, toa new and useful heater particularly for vehicles which have a water cooled internal combustion engine and which includes a separate burner for supplying combustion gases for heating the air and which has means for cooling combustion gases before they enter the gas/air-heat exchanger and further means for pumping the combustion gases out of the heater continuously.

2. Description of the Prior Art There are many known types of heating systems which are employed as auxiliary equipment for motor vehicles or ships. Such heaters referred to as stand heaters are also used with advantage for vehicles having air cooled internal combustion engines but they are being used increasingly in vehicles with water cooled internal combustion engines. They comprise a separate heater which is independent of the engine with separate heating air distribution systems. It is known to try to preheat the engine by means of separately generated heat but such solutions are expensive since the heat must be supplied to the heating air through two heat exchanges, a gas/water-heat exchanger and a water/airheat exchanger.

SUMMARY OF THE INVENTION The present invention provides an improved heating system designed as a stand heater by means of which the heat generated in a device which is independent of the operation of the engine is fed to the air passages of the gas passages of the water heater of a vehicle so that with this heating system it is possible to use parts which already exist in the vehicle and in addition, it is possible to use the heater as a stand heater, i.e., with the engine standing still, and also for the purposes of preheating the engine. The invention provides a space air heating system which includes an independent burner which operates separately from the engine and which discharges into a gas/air-heat exchanger which may be arranged directly alongside the liquid/air-heat exchanger which is heated by the cooling water of the internal combustion engine. The burner includes means for admixing secondary air to the gaseous products of combustion which are generated in order to reduce their temperatures to a reasonable range for circulating through the gas/air-heat exchanger. In addition a suction fan is connected to the outlet of the gas/air-heat exchanger to ensure that the gases are always continuously circulated therethrough and do not leak in through the space heating air.

It was found particularly expedient to provide a heating gas/air-heat exchanger which operates separately in conjunction with the burner as an independent unit and this unit is advantageously detachably connected into a space air heating housing directly adjacent the water air heating unit which is normally provided in such a housing for circulating liquid from the engine cooling system. Thus, the heating portion which is referred to as a stand heater can be installed in the heater which operates only at the times of operation of the main engine. The invention provides a construction in which the stand heater having a gas/air-heat exchanger and an independently operable burner. for generating heating gases, is arranged with a vehicle space heater having a liquid air heat exchanger which is operated by the liquid of the engine cooling system. The hot gases which are generated in the burner of the stand heater are conducted through the heat exchanger which is arranged either before or behind the water/air-heat exchanger. The heating gases which are generated and which issue from the burner are brought to a temperature of about 300 to 400C and therefore, secondary air is added to the gases, for example in a ratio of about 1.3 to 1.4 through a supply air feeding device between the burner and the gas/air-heat exchanger. Particularly suitable as feeding device is an injector with the combustion gases passing centrally through the injector conduit into the gas air heater and the additional air or fresh air supplied annularly around the central stream of combustion gases. The combustion gases are then reduced in temperature from about 1,500C at the time they leave the combustion chamber, to the temperature range suitable for circulation through the gas air heater to operate in the temperature range 300 to 400C. Therefore, no excessively high temperature will appear in the combustion air stream which passes the gas/air-heater and moves in heat exchange contact with the liquid/airheat exchanger.

The burner is advantageously designed with a central combustion chamber which is surrounded by walls defining an annular flow space for additional air. The construction defines a combustion chamber with an opening centrally between the annular air flow in the form of a flame nozzle and by adding a supply of secondary air in the annular stream there is no resonance phenomena so that it is possible to conduct the heating gases through a relatively thin and long connection pipe to the gas/air heat exchanger. The control of the burner and the supply of fuel are effected in a known manner as in the known heaters. For delivering the fresh air to the heater, there is an arrangement in which the fresh air fan which already exists in the water-series heaters is employed. If the gas/air-heat exchanger is arranged ahead of the water/ainheat exchanger, there is an additional possibility of preheating the water in the engine cooling system in order to facilitate the warmup of the engine. Heat may be supplied to heating air which in turn transfers it to the liquid of the heat exchanger corresponding to from 20-30 percent of the heating power. An additional electric waterpump is provided for the circulation of hot water through the internal combustion engine.

Accordingly, it is an object of the invention to provide a space heater particularly for vehicles having a water cooled internal combustion engine which comprises a housing having a space heating air inlet and a discharge spaced from the inlet and with a gas airlheatexchanger and a water/air-heat exchanger located within the housing between the inlet and outlet, and wherein there is a separate burner for generating combustion gases which are mixed with additional air to lower their temperatures then to direct them into a gaslair-heat exchanger arranged alongside the water/airheat exchanger; and wherein the gases are withdrawn from the gas/air-heat exchanger by a suction pump connected thereto.

A further object of the invention is to provide a space heater which is simple in design, rugged in construction and economical to manufacture.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a schematic sectional view of a space heater constructed in accordance with the invention; and

FIG. 2 is an enlarged sectional view of the burner used with the space heater shown in FIG. 1.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in particular, the invention embodied therein comprises a space heater generally designated 50 which includes a housing 1 having an inlet opening 7 at one end for space heating air and at least one or more discharges 10, at the opposite end. The heater 50 is of a type which includes a liquid- /air-heat exchanger 3 which receives heating liquid from the cooling system of an internal combustion engine 2.

In accordance with the invention the heating of the heater 50 is supplemented by a separate gas heating device generally designated 52 which includes a gas/airheat exchanger 6 which is arranged within the housing 1 preferably upstream and alongside of the liquid/air heat exchanger 3. The housing 1 also carries a fan motor 9 which drives a fan 8 to circulate the space heating air through the inlet 7 through the gas/air-heat exchanger 6, the liquid/air-heat exchanger 3 and then out through one or more openings 10, 10' for space heating purposes.

In the operation of the vehicle, the cooling cycle comprises the heating air fan 8 which circulates the heating air over the liquid heat exchanger 3 and this heat exchanger is supplied with water from the cooling system of the engine 2 through inlet connection line 11 under the force of an electrically driven waterpump 12 through a valve 13 and a conduit 14 into the liquid/airheat exchanger 3 and then is returned through a return line 15 to the engine 2. The liquid which is circulated gives off its heat to the space heating air which passes through the housing 1. Since this known type of cooling cycle can only be used for heating the vehicle when the engine is running so that the cooling water system is maintained at a predetermined temperature for example, 80C, it is necessary that there be some additional heat source when the engine 2 is not running. According to the invention this additional heat is supplied through the heating unit 52 which includes the heat exchanger 6 which is detachably arranged preferably between the fan 8 and the liquid/air-heat exchanger 3.

The gas/air-heat exchanger 6 includes an inlet which is connected to the discharge of the burner 4.

As best seen in FIG. 2 the burner 4 includes an annular wall 19 having an inlet 20 at one end for additional or secondary air and a discharge 18 at the opposite end which is connected at 17 to the inlet of the gas/air-heat exchanger 6. The burner 4 also includes an inner housing 54 which encloses a combustion chamber 21. The combustion chamber 21 is provided with a lateral connection 24 defining a prechamber into which fuel is admitted through a conduit 25. Combustion air is directed inwardly through a combustion air supply fitting 23 and is directed by a fan 22 into the combustion chamber along with the fuel from the conduit 25 when it is ignited by a spark plug 56 to generate combustion gases. These combustion gases are at a temperature of from 1,200 to 1,600C in the combustion chamber 21 so that they are mixed with additional or secondary air which is fed through the inlet 20 at the location of a narrow throat section or nozzle 16 in which the annular air flow combines with the central combustion gas flow flowing into the discharge portion 18. The secondary air is added to an extent such that the temperature of the combustion gases combined with the air is such that it will be in a range of about 300 to 400C at the gaslair-heat exchanger 6.

The housing 19 of the burner 4 supports the inner wall housing 54 on straps 27. A cylindrical part 28 protrudes into the combustion chamber 21 centrally within the guide vanes 22 for guiding the combustion air which is delivered through the combustion air inlet fitting 23 into the combustion chamber 21. The spacing of the inner chamber housing 54 from the outer housing 19 is such that there is an annular flow passage 26 for the passage of the secondary air which comes in through the inlet 20. The additional air intermixes intimately with the combustion gases due to the injectortype nozzle formation at the location 16 so that the temperatures of the combustion gases are reduced to the desired value.

Because of the construction of the housing 54 within the housing 19, and due to the circulation of the outside additional air or secondary air around the combustion chamber 21, the burner operates without any resonance phenomena appearing in the pipe connections 18 to the gas/air-heat exchanger 6. Thus, the burner can be operated even without additional sound absorbing means.

The gas/air-heat exchanger 6 of the invention is preferably designed as a tubular heat exchanger. The pipes are preferably flattened so that they have a substantially elliptical cross section and a particularly good heat transfer is assured.

In accordance with a further feature of the invention the combustion gases are continuously circulated through the inlet 20 and into the gas/air-heat exchanger 6 and then out through the outlet of the heat exchanger (not shown) through a suction line 58 which connects to the suction of a suction gas pump 5. The suction gas pump 5 discharges the combustion gases after they have given up their heat in the heat exchanger 50 through a conduit 60. The operation of the suction pump 5 ensures that the gases will be continuously withdrawn from the gas/air-heat exchanger and that there will be no leakage of gases into the space heating air which is circulated therethrough in the space heater 50.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A space heater particularly for vehicles having a water cooled internal combustion engine, comprising a tubular housing having a space heating air inlet at one end and a space heating air discharge at an opposite end spaced from said space heating air inlet, a gas/airheat exchanger disposed across said tubular housing and having a gas inlet and a gas outlet, and an air/liquid-heat exchanger disposed across said tubular housing and located in said housing between said air inlet and air outlet, fan means for directing space heating air through said air inlet through said gas/air-heat exchanger and said air/liquid-heat exchanger and out through said air outlet, means for connecting the airlliquid-heat exchanger to the engine water cooling system for supplying cooling water to said air/liquid-heat exchanger, 21 separate burner outside of said tubular housing having a combustion chamber with means for adding fuel and air thereto and for igniting the mixture for generating combustion gases therein, conduit means connecting said combustion chamber to said gas inlet of said gas-air inlet exchanger for flow therethrough in heat exchange relationship with air passing through said tubular housing, means for adding additional air to the combustion gases passing through said conduit means between said combustion chamber and said gas inlet to cool them, and a gas suction pump connected to said gas outlet for withdrawing the combustion gases from said gas/air-heat exchanger.

2. A space heater, according to claim 1, wherein said burner and said gas air heater and said gas suction pump comprise a separate unit which is detachably associated with said housing.

3. A space heater, according to claim 1, wherein said burner includes a housing having inner and outer walls with the inner walls defining a combustion chamber and with the space between said inner and outer walls defining an annular air flow space for additional air, said combustion chamber terminating in a combustion gas central discharge within the annular flow space for the additional air and being shaped to form an injector at such location for inducing the flow and intermixing of said combustion gases and said additional air. 

1. A space heater particularly for vehicles having a water cooled internal combustion engine, comprising a tubular housing having a space heating air inlet at one end and a space heating air discharge at an opposite end spaced from said space heating air inlet, a gas/air-heat exchanger disposed across said tubular housing and having a gas inlet and a gas outlet, and an air/liquid-heat exchanger disposed across said tubular housing and located in said housing between said air inlet and air outlet, fan means for directing space heating air through said air inlet through said gas/air-heat exchanger and said air/liquid-heat exchanger and out through said air outlet, means for connecting the air-/liquid-heat exchanger to the engine water cooling system for supplying cooling water to said air/liquidheat exchanger, a separate burner outside of said tubular housing having a combustion chamber with means foR adding fuel and air thereto and for igniting the mixture for generating combustion gases therein, conduit means connecting said combustion chamber to said gas inlet of said gas-air inlet exchanger for flow therethrough in heat exchange relationship with air passing through said tubular housing, means for adding additional air to the combustion gases passing through said conduit means between said combustion chamber and said gas inlet to cool them, and a gas suction pump connected to said gas outlet for withdrawing the combustion gases from said gas/air-heat exchanger.
 2. A space heater, according to claim 1, wherein said burner and said gas air heater and said gas suction pump comprise a separate unit which is detachably associated with said housing.
 3. A space heater, according to claim 1, wherein said burner includes a housing having inner and outer walls with the inner walls defining a combustion chamber and with the space between said inner and outer walls defining an annular air flow space for additional air, said combustion chamber terminating in a combustion gas central discharge within the annular flow space for the additional air and being shaped to form an injector at such location for inducing the flow and intermixing of said combustion gases and said additional air. 